A fuel injection valve, wherein a convex portion is prominently formed in an orifice plate having orifices, plural recesses are formed at the convex portion, and an opening (outlet) of each of the orifices is formed at the bottom face of the relevant recess, has heretofore been known (for example refer to JP-A No. 77843/2007). In the fuel injection valve, the bottom face of a recess is formed perpendicularly to the axis line of the relevant orifice, consideration is made so that a fuel can be injected at the same time in a circumferential direction from outlets of the orifices. Further consideration, in forming process of the orifices, is made so that bending force may not be exerted on a punch when press forming is applied to a blank for the orifice plate. Further, a length of an orifice is adjusted by changing a depth of the relevant recess.
In the conventional technology, the functions of reducing the bending force exerted to a punch and adjusting the lengths of orifices are given by recesses each of which has only one step. As a result, press forming of orifices and recesses is restricted. For example, the angle between a punch and a press forming face cannot be largely deviated from 90 degrees or a thickness of the punch has to be used if it is attempted to largely deviate the angle. When deep recesses each of which has a large step are formed with a thickness of the punch, the work may weaken the strength of members used for the forming of the orifices.
When the strength of members forming orifices weakens in process of forming plural orifices and recesses, the next press forming is hardly applied to the succeeding orifices and recesses in some cases. Then, as the number of orifices increases, the degree of difficulty in press forming may increase and the degree of freedom in the design of orifices (a number, an inclination angle, an interval, etc.) may be restricted further.
Further, in the case where a large number of orifices are formed, when deep recesses of large diameters are intended to form, it is concerned that recesses of adjacent orifices and moreover a recess and an orifice may interfere with each other. In particular, when it is attempted to change an inclination angle of each orifice with respect to a center axis line of a fuel injection valve for each orifice and orient the orifices in desired directions, interference between recesses or between a recess and an orifice tends to occur among specific orifices. As a result, it is concerned that the degree of freedom in the design of orifices may reduce.
An object of the present invention is to increase the degree of freedom in design and the workability of orifices formed by press forming and used in a fuel injection valve.